THE GENUS CALOSOMA. 95 



August feeding practically ceased, the beetles spending most of their 

 time in the earth in the jar. 



Mr. H. F. Wickam conducted cage experiments at Koehler, N. Mex., 

 in August, 1914, to determine if the beetles would kill and eat grass- 

 hoppers and H. oliviae caterpillars and if preference was shown. 

 The experiment was started August 10 and both varieties of living 

 prey were supplied. In one cage under observation 33 days, 33 large 

 H. oliviae larvae and two grasshoppers were killed and eaten and 

 in another cage containing 3 beetles under observation 15 days, 6 

 caterpillars and 1 grasshopper were killed and eaten. Some con- 

 trasting experiments were conducted at the time where killed grass- 

 hoppers were supplied the beetles with living H. oliviae caterpillars 

 and as a result many more of the former were consumed than of the 

 latter. Dead caterpillars were not eaten so readily as living. These 

 experiments indicate that accessibility to a particular host is the im- 

 portant factor in the partial control by a predator. Practically the 

 same results were secured in like experiments with C. obsoletum Sslj. 



REPRODUCTION AND HIBERNATION. 



Two males and 1 female in breeding jar from July 28 to September 

 13, 1913, deposited at least 6 eggs, 3 of which hatched. Copulation 

 was observed several times during the season. In another j ar contain- 

 ing the same number of adults, 18 eggs were deposited, 15 of which 

 hatched. The first eggs were deposited by beetles in confinement 

 in 1914 on June 9 and the last August 4. In one cage containing 

 more than one female, 156 larvae hatched and in another 162 hatched. 

 The time in the egg stage varied from 7 to 12 days. 



The first adults issued from hibernation in New Mexico in 1914 

 on or before June 5 and adults were seen in the field up to September 

 2 and even October 10, the latter dates indicating the late periods 

 of entering hibernation. One beetle remained on the surface of the 

 earth in a jar at Melrose Highlands, Mass., as late as October 20, 1915. 

 They went into the soft earth to the bottom of the j ar, a depth of 5 

 to 6 inches, for hibernation. 



The maximum length of life of adults of this species has not yet 

 been determined but they undoubtedly live 2 years or more. 



FIELD OBSERVATIONS AND ECONOMIC IMPORTANCE. 



June 5, 1914, one female was collected near Dorsey Reservoir and 

 on the same date Messrs. W. R. McConnell a^nd T. S. Wilson collected 

 a large number to the south of Koehler, N. Mex. -The beetles were 

 found under rubbish, in the bed of a dry creek. Hemileuca larvae 

 were present in the vicinity but were not very numerous. June 28, 

 1915, Mr. D. J. Caffrey observed north of Maxwell, N. Mex., a 

 female of this species feeding upon a second-stage larva of H. oliviae 

 Ckll. and in the region of Chico on September 2 observed a larva of 

 this species or obsoletum Say feeding upon a partly formed pupa of 

 the same host. 



The adults were observed in the field in New Mexico in common 

 with 0. obsoletum Say at periods from June 5 to about October 10, 

 always associated with its host, H. oliviae Ckll., and apparently accom- 

 plishing a great deal in the natural control of the above pest. Mr. 

 Caffrey observed the beetle larvae feeding upon Hemileuca pupae. 



